Allowed Android Device Manager (ADM) to locate your device (turned on by default). This can changed in the Google Settings app.

Allowed ADM to lock your device and erase its data (turned off by default).

Android Device Manager is
a Google’s official and easy-to-use tool to track your Android phone or
tablet. The best thing about it is that you don’t need to install an
app to be able to track your devices. The only requirement is that your
device is connected to your Google account, turned on and connected to
the internet.

Besides tracking, letting your phone ring and wiping your phone
(which has to be enabled manually), Android Device Manager doesn’t offer
more options to remote control your phone. Hopefully, Google will work
on that and offer more features, such as taking pictures in case it got
stolen and you want to know who took it.
In case there’s no laptop around when you lose your device, you
can also use someone else’s Android phone to track it. Instead of using
the mobile browser, you can also use the Android Device Manager app. If you the other phone doesn’t have it, simply download it here.
You can sign in using the guest mode and your Google account
credentials. Now you should be able to track your lost device, let it
ring or wipe its data.

Are you not able to locate your phone this way? This
can happen for several reasons. The one you should hope for, is that
your device is simply not connected to the internet or turned off. In
that case, simply keep trying to track it until it (hopefully) connects
to Google’s services again.

In case it got stolen, it’s possible that the thief has
disconneced your device from your Google Account. If that happens,
neither Android Device Manager nor any other tracking tool will be able
to locate the device, since it’s necessary to be logged into your Google
Account. This doesn’t apply to previously installed tracking apps but
in this scenario there are none on the phone. However, there’s one last
resort but more on that later.

2. Remote control and track your smartphone with Android Lost

UPDATE: Due to Android API updates, Android Lost can’t be activated remotely on devices running Android 3.0 or higher.Requirements:

Your device is connected with your Google account.

Your device has access to the internet.

You’re not running Android 3.0 or higher.

This is a more complicated way to track your phone.
Basically, you need to install the tracking app ‘Android Lost’ on your
phone and activate it by sending it an SMS (this can be done from any
phone). How do you install something when you don’t have your phone with
you? That’s very easy. You can install any app on all your registered
devices directly from your browser through the Google Play website. Simply navigate to the Android Lost app and click the install button.

The remote installation process of Android Lost is very
straightforward and only requires that your phone is still connected
with your Google account. However, in case of theft, you have to hope
that the thief doesn’t disconnect from your account.